The present invention relates to an L- or U-shaped packing box erected by folding a single base sheet.
A packing box of corrugated cardboard is known which has an L- or U-shaped portion bent at right angle and rising from one or opposite ends thereof for receiving an L- or U-shaped product.
Japanese Utility Model Laid-Open Publication No. SHO-60-92918, for example, discloses a packing box of corrugated cardboard for receiving and packing an L-shaped product. The disclosed packing box comprises a single base sheet in its unfolded state. In an erected state, the base sheet has a rectangular bottom portion forming a packing portion for receiving a horizontal part of the L-shaped product, and a rectangular rear portion forming a packing portion for receiving an upright part of the L-shaped product. Plural flaps forming the horizontal part extend outwardly from the opposite sides of the bottom portion. Other flaps forming the upright part extend outwardly from opposite sides of the rear portion. Thus, the disclosed corrugated cardboard packing box does not have a sideways-long rectangular configuration when it is exploded or unfolded.
An automobile bumper has a generally flat front portion and opposite ends bent backwardly and hence is generally U-shaped. For receiving and packing such a U-shaped bumper in a corrugated cardboard box, the box is required to define a U-shaped internal space for accommodating the bumper and hence to have a U-shaped outer configuration.
Such a U-shaped packing box is known from, for example, Japanese Utility Model Laid-Open Publication No. HEI-2-48516. As shown in FIG. 2 of the publication, the disclosed packing box comprises a U-shaped container member for receiving a U-shaped product, and a U-shaped cover member for covering the container member. The container member is opened at its upper side. The cover member is opened at its lower side.
In the corrugated cardboard packing box of Japanese Utility Model Laid-Open Publication No. SHO-60-92918, the base sheet has a complex configuration and hence its cutting operation is tedious and produces wasted parts and low yielding. In addition, most part of the packing box erected by folding the base sheet is single-layered, though limited part or parts are double-layered. Consequently, when the packing box is provided in a large number and laid horizontally one over another in a stacked fashion, ones positioned at a lower level are applied with a large weight and may possibly be deformed undesirably, because they have limited vertical rigidity. For example, when the corrugated cardboard boxes containing press-shaped automobile front fenders are laid one over another in a stacked fashion, lower-leveled boxes may possibly be crushed. This directly badly affects the front fenders contained in the boxes and causes deformation of and scratches on the fenders. Thus, the number of boxes that can be stacked is limited to such extent that lower-leveled boxes are freed from undesired deformation.
Since the U-shaped packing box disclosed in Japanese Utility Model Laid-Open Publication No. HEI-2-48516 comprises two different members, namely, the container and cover members, it requires an operation for erecting the container member and another operation for erecting the cover member, thereby increasing an increased number of man a hours for erection. In addition, two different cutting-punching machines, one for cutting-punching the container member and the other for cutting-punching the cover member, are required, thereby adding up the costs of production. For making the box, it is required to first erect the container member, then to put the U-shaped product in the container member and thereafter to fit and join the cover member. Consequently, it is not possible to perform the packing operation during erection of the box.
As shown in FIGS. 4 and 5 of Japanese Utility Model Laid-Open Publication No. HEI-2-48516, the illustrated packing box includes the base sheet with flaps projecting outwardly from opposite ends thereof and hence has a generally H-shaped configuration. Accordingly, the cutting-punching operation with respect to the base sheet becomes tedious and wasted parts are produced, thereby decreasing the yielding. Before erection, base sheets of this kind are usually horizontally laid one over the other in a stacked fashion and kept in a storage space. In so doing and upon their shipment and erection, the stacked base sheets are liable to be deformed and damaged, because each base sheet has flaps sticking out to easily get caught or be hit by obstacles.
The thus-erected packing boxes are mostly single-layered. Thus, when the boxes are stacked, lower leveled ones of the boxes and the products packed therein may be easily deformed and damaged, because their vertical rigidity is weak. This is particularly so when the product is a resinous bumper.
To enable the stacked storage of the packing boxes, one may propose to increase the rigidity of the boxes by making them dual-boxed, that is, forming them by an inner box of corrugated cardboard and a rigid outer box enclosing the inner box. However, this is not advantageous in that increased production costs are required.
Further, since the boxes are still single-layered in most parts, there remains a fear that the products will be found damaged when they are taken out of the boxes. Moreover, the boxes can endure only a one-time use, or two-time use at the most, and are not suited for repeated uses.
It is therefore an object of the present invention to provide an L- or U-shaped packing box which is formed by folding a single sheet of corrugated cardboard such that an automobile L-shaped front fender or U-shaped bumper can be received and packed, and which can endure stacked storage and allows for repeated uses.
According to an aspect of the present invention, there is provided a packing box for packing a product having at least one bent portion, the packing box being erected by folding a single sideways-long rectangular base sheet along folding to lines and slits formed on the base sheet such that the product including the bent portion is entirely covered, characterized in that the base sheet comprises: a first folding line discontinuously extending longitudinally of the base sheet; a second folding line continuously extending longitudinally of the base sheet in parallel with the first folding line for, together with the first folding line, dividing the base sheet into three laterally separated regions, the three regions including opposed outer regions and a central region positioned therebetween; a plurality of first short slits provided on one of the outer regions such that they extend from a long side of the one outer region to the second folding line; a plurality of second short slits provided on the other one of the outer regions such that they extend from a long side of the other outer region to the first folding line; a plurality of long slits provided on the other outer region such that they extend from the long side of the other outer region to the second folding line; a plurality of third folding lines provided on the one outer region such that they extend from the long side of the one outer region to the second folding line in axially aligned relation to the long slits; a plurality of fourth folding lines provided on the central region such that they extend between the first and second folding lines in axially aligned relation to the first and second short slits; and a plurality of flaps defined by the first and second folding lines, the third and fourth folding lines, the first and second short slits, and the long slits, so that the base sheet can be folded along the third and fourth folding lines and the slits into a tubular shape and then into the packing box having at least one bent portion by folding at least part of the tubular-shaped base sheet with relative to another part of the tubular-shaped base sheet.
In the thus arranged packing box, since the packing material comprises a single sideways-long rectangular base sheet which is simple in configuration, its cutting operation becomes easy and wasted parts can be kept to a minimum, thereby achieving high yielding. Further, since the base sheet is of non-complex rectangular configuration, folding lines and slits can be easily formed on the sheet. When a plurality of such base sheets are laid one over the other in a stacked fashion, they will not be damaged, because they are of simple rectangular configuration with no parts sticking out. They will not be damaged upon shipment, either.
By folding part of the base sheet along the long slits, a box-shaped upright portion is provided for enclosing the bent portion of the product. The first and second folding lines, the third and fourth folding lines, the short slits and the long slits are all formed transversely and longitudinally on the base sheet so that the flaps defined by them have no parts projecting outwardly. In addition, an apparatus for forming those folding lines may be simple in construction.
Desirably, the packing box has at least two-layered wall portions so that it can endure a vertical load applied when the box is positioned at a lower level of a stack of such boxes. The base sheet may be folded such that wall portions of the box to which a large load is applied become three-layered and most wall portions of the box become two-layered. Consequently, the erected packing box has increased rigidity. Thus, there is no fear that the box with the product packed therein will be deformed when it is positioned at a lower level of a stack of such boxes, thereby enabling reuse of the box and hence reduction in the costs thereof.
In a preferred form, the packing box comprises a box-shaped body portion erected by folding the base sheet along the folding lines and the slits, and a box-shaped upright portion integral with and rising at right angle from at least one end of the body portion.
It is desirable that the packing box has an L-shaped configuration so that it can pack an L-shaped product. The L-shaped product may be an automobile front fender. It is also desirable that the packing box has a U- or channel-shaped configuration so that it can pack a U- or channel-shaped product. The U-shaped product may be an automobile bumper.
In a preferred form, the base sheet comprises a sheet of corrugated cardboard. The base sheet may be made from a water-, humidity- and wear-resistant material.
The first folding line may comprise six line segments occurring intermittently along the length of the base sheet. The second folding line may comprise six line segments occurring continuously along the length of the base sheet. The separate folding line provided on the central region may comprise four folding lines. The separate folding lines provided on the either outer side region may comprise two folding lines. The short slits provided on the either outer side region may comprise three short slits. The short slits provided on the other outer side region may comprise seven short slits. The long slits may comprise two slits extending from a long side of the other outer side region to the second folding line. The either outer side region may comprise six flaps defined by the second folding line, the two folding lines provided thereon and the three short slits provided thereon. The other outer side region may comprise ten flaps defined by the first folding line, the seven short slits provided thereon and the two long slits provided thereon. The central region may comprise six flaps defined by the first and second folding lines, the four folding lines provided thereon and the two long slits.
The first folding line may comprise eight line segments occurring intermittently along the length of the base sheet. The second folding line may comprise eight line segments occurring continuously along the length of the base sheet. The folding lines provided on the central region may comprise four folding lines. The folding lines provided on the either outer side region may comprise four folding lines. The short slits provided on the either outer side region may comprise three slits. The short slits provided on the other outer side region may comprise eleven slits. The long slits may comprise four slits extending from a long side of the other outer side region to the second folding line. The either outer side region may comprise eight flaps defined by the second folding line, the four folding lines provided thereon and the three slits provided thereon. The other outer side region may comprise sixteen flaps defined by the first folding line, the eleven short slits provided thereon and the four long slits. The central region may comprise eight flaps defined by the first and second folding lines, the four folding lines provided thereon and the four long slits.